1. Field of the Invention
The present invention is related with a control information recording method and apparatus for recording in advance, onto an information record medium of WO (Write Once) type (hereafter, referred to as a DVD-R (Digital Video or Versatile Disk-Recordable)) among information record media whose recording densities are dramatically improved over conventional CDs (Compact Disks) and the like represented by the DVD, control information such as address information, a synchronization information etc. (hereafter, referred to as "pre-information") required to record and reproduce the substantial record information such as video information and audio information to and from the DVD-R. The present invention is also related with an information recording method and apparatus for recording the record information onto the DVD-R while reproducing the pre-information from the DVD-R on which the pre-information has been already recorded.
2. Description of the Related Art
In an information record medium such as a WO type postscript optical disk and the like, the pre-information for a position retrieval at a time of writing the record information is recorded in advance onto the information record medium at a pre-format stage in manufacturing the information record medium. As a method of pre-formatting this pre-information, an information record track (a groove track or a land track) for recording the record information is wobbled in a form of a wave so as to record the pre-information. Alternatively, a pre-pit is formed on a portion different from a portion where the record information is recorded on the information record track, so as to record the pre-information.
However, in a case of the pre-format of the pre-information by the wobbling, the information record track itself is swung to the right and left relative to a rotation direction of the information record medium on the basis of a wobbling signal. This results in a problem that a C/N ratio (Carrier to Noise ratio) is poor because of a restriction in a modulation degree of the wobbling signal (wobbling amplitude) due to a relation to an adjacent information record track. Further, considering an interference resulting from the adjacent information record track since the adjacent information record tracks are close to each other by the wobbling, it is difficult to make a track pitch narrow. This results in a problem of limitation in improvement of the recording density.
On the other hand, in a case of the pre-format of the pre-information by the pre-pit, since the pre-pit is formed on the information record track, the recordable amount of the substantial record information is reduced by the amount of the formed pre-pit. This results in a problem of a poor utilization efficiency of a disk record surface.